Transmission control protocol (TCP) is a connection-orientated, reliable, and byte-stream-based transport layer communication protocol, and is widely applied to the Internet and a mobile network. The TCP protocol is originally designed for a wired network environment condition. An assumption implicitly exists in the TCP protocol used for wired transmission: All packet losses are caused by network congestion. However, this does not hold true for a wireless network or the assumption cannot be well met in a wireless network environment. The wireless network environment has features such as small bandwidth, a large delay, and mobility. Consequently, working efficiency of TCP in the wireless network is reduced.
To resolve the problem, a TCP proxy mechanism is used. To be specific, a network device is disposed between user equipment (UE) and a server, there is a TCP connection based on an air interface wireless environment between the UE and the network device, and there is a wired TCP connection between the network device and the server, so as to optimize the working efficiency of TCP in the wireless network. However, when the UE moves from one cell to another cell, parameters used to control a TCP connection between the UE and the server are lost in a source network device. Consequently, a target network device cannot maintain the TCP connection between the UE and the server based on these parameters, and accordingly service continuity cannot be ensured.